


Fate Swapped

by Catsitta



Series: Fated [2]
Category: Ancient Greek Religion & Lore, Undertale (Video Game)
Genre: Adult Frisk (Undertale), Alternate Universe - Ancient Greek Religion & Lore Fusion, Alternate Universe - Role Reversal, F/M, Family Issues, Female Frisk (Undertale), Humor, Inaccurate Ancient Greek Religion & Lore, Inspired by Hades and Persephone (Ancient Greek Religion & Lore), Kidnapping, Light Angst, Marriage, Romance
Language: English
Status: Completed
Published: 2020-03-24
Updated: 2021-02-08
Packaged: 2021-02-28 23:14:13
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 8,043
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23295334
Author URL: https://archiveofourown.org/users/Catsitta/pseuds/Catsitta
Summary: Her mother should have been more specific when she said she had to marry.In which the Goddess of Spring abducts herself a husband, and said husband isn’t as bothered by the fact as he thinks he should be.Frans | Fated AU | Role Reversal
Relationships: Frisk/Sans (Undertale)
Series: Fated [2]
Series URL: https://archiveofourown.org/series/1662937
Comments: 104
Kudos: 509





	1. Chapter 1

**Author's Note:**

> For Quarantine Frans Week - Day Two: Role Reversal
> 
> Can be read separate from 'Bride of the Underworld'. 
> 
> To be quite honest this whole fic started as a doodle and a joke. Now it exists. Thank you Shayromi you instigator, this was a terrible amount of fun.

“so uh, you greet everyone this way or am i just special?” Sans squirmed against the vines holding him fast around the middle, arms pinned to his sides, his whole body dangling off the ground. The plants darkened and withered from his deathly aura—an effect he couldn’t really stop—but the goddess controlling them was quick to revitalize them in response. It was rather fascinating, and if he wasn’t being actively held against his will, he might have asked to test their gifts against each other, for he had never encountered another who could combat decay like she. “apologies if i’m mistaken, but you are lady spring, yes?” He’d never met the Queen of Gods’ halfling daughter turned goddess, but he heard talk from the other gods. How she grew up sequestered in the Heavens, little more than a rumor until one day she escaped to the Surface and discovered her Name. After which she became renowned for her wild and spoiled antics as she ran amok in the mortal world, bucking any mantle that her birthright might have entitled her to.

Sans heard about her turning gossipy nymphs into plants and attacking suitors with thorny plants that she commanded like hydras. Some described her as wild and savage in bare feet and a wicked smile. Others told of her being a delicate beauty that tempted until one came too close, that laughed when the unassuming fell into her trap. Of course he never went looking—never cared to—for what reason did he have to go searching for the Queen’s ill-mannered daughter? Yet somehow he found her without looking. Sans was working, collecting souls as his brother kept order Below, when he was distracted by a rock. A pretty rock. Some might say it was little more than a river stone. But it drew his attention all the same. He was about to pocket it when there was a flash of red in the corner of his vision, a determined soul, and suddenly, he was bound. 

The goddess in question stepped closer, emerging from the craggy caven in which she must have been sheltering, circling him like a feline deciding how best to pounce, a hand to her lips, a tilt to her head. She wore royal purple, though the garment was torn and grass-stained, her feet were bare, and a crown of golden flowers laid askew upon her head. She was an uncultured rose growing untamed in the middle of a forgotten garden, no one around to trim her thorns. 

“Hm. Maybe. Maybe not. Depends who is asking,” she said at last, drawing close enough that he could feel her breath on his cheekbone. He couldn’t help the heat that flushed his skull. Nobody but his brother had ever been this close, and Papyrus didn’t exactly hold his hand now that he was all grown up and ruling the Underworld. The weight of the crown rested heavy on the younger god of Death, but he was better suited to ruling than Sans, and even the Fates were in agreement that Sans was not the one who was meant for the throne. So long ago he abdicated and spent his days as he did when he was first Named, reaping souls. “Who are you?”

“death,” Sans drawled. Spring quirked a brow at him and he returned the gesture. “pardon, death the elder.”

“Yes, but what is your name?” She reached out and he flinched back as best he could while bound. She might be an immortal, but not even gods liked the feeling of being shattered. Just because she would get better didn’t mean he wanted to invite whatever ire it would cause. “I’m not going to hurt you, you ridiculous man.” 

“didn’t anyone teach you manners?” Sans groused, deepening his voice and attempting to be stern. “how would you appreciate it if i tried to touch you and asked for your true name without so much as an introduction?”

Spring narrowed her eyes and her mouth pinched into a curt little frown, “You are the one that intruded in my home. I get to ask the questions!” At his stare she huffed, cheeks puffing, “My name is Frisk. Use it. None of this Lady Spring nonsense. I hear enough of it from my mother. Now what is your name?”

“rude and demanding. now i see why you live in a cave like a barbarian.”

For a moment, her soul flared, that vivid red he learned to be wary of in mortals, her brown eyes almost taking on the same hue to his perception. Then her frown faded and a grin split her face, “You’re the one all tied up here. Completely at my mercy. And here you are insulting me.”

“what are you going to do about it, kill me?” Sans deadpanned. Frisk’s lips twitched and she began to laugh. When she regained herself, she flipped her hair and gave him a look that he couldn’t quite describe. 

“Hm. No. Worse, I think I’ll keep you.”

Sans dropped his head and sighed, “fine, fine. you drive a hard bargain. if it would appease you, my name is sans, and i am quite busy so if you would release me…”

“Hm. No.”

“no?”

“No,” Frisk reached up and pulled back his hood, thumbs brushing his cheekbones. He flinched, waiting for her to shatter...but nothing happened. She remained smiling and whole as she proceeded to straighten his disheveled robes. “There. See, not going to hurt you, you can stop flinching.” She patted his skull and Sans froze with disbelief. Long ago, when he was young, before Papyrus was born and he was the only God of Death and Lord of the Underworld, he was given council from the Fates. On the day they said he would shed his crown, they claimed that there would be One that would be a bride for him that was immune to his touch. He searched and was hopeful for many eons, but eventually, he stopped looking, having seen countless souls, and not a one the match the Spinners said they wove into his future. “I have decided to claim you as my captured bride, and we will be married posthaste in accordance to our ancient laws.”

Sans blinked. There was indeed a law as old as the Pantheon itself about abducting suited brides. But there were a few matters to question. The first being he was very much a male, and second...married? Why in Asgore’s name did she want to marry him, much less claim him as her spouse through an ancient rite? “heh. real humerous. you can let me go now.” He willed his aura stronger, causing the vines to blister and blacken, shriveling quicker than before. Even the flowers and grass he wasn’t touching began to wilt. Frisk stood her ground, and there was a static to the air as their powers clashed, her defying death itself with every ounce of stubborn willfulness in her soul. 

They were at a standstill until she decided to cheat. Surging forward, she cupped his skull and touched their foreheads together, “I promise I’m not joking. What if I kiss you to prove that I’m being earnest?”

He was ashamed to admit that a small, forgotten piece of him brightened at her proposal. Yearned for what she promised. This was her. The wife the Fates promised. She was offering him all he ever wanted! Certainly, it was unconventional and something peculiar was most definitely afoot, but stars above, he wanted it to be real. He wanted that kiss. He wanted her arms around him and whispers of sweet nothing and all the stupid, simpering romantic gestures that he heard about but could never indulge in. So instead of continuing to fight like he should have, he swallowed all common sense and tilted his face up, his teeth closer to her lips. 

She closed the distance and kissed him. It was a brief little kiss. Little more than a peck. But it left him limp in the vines, staring at her, suddenly quite helpless to whatever it was she wanted. “l-look,” he cleared his throat. “tibia honest, i don’t think—” Where were his words? He found her, his future wife! But this wasn’t exactly how he thought their courtship would go at all. There was supposed to be a courtship, for one! And she wasn’t supposed to be the wild, spoiled daughter of Mother Nature, nor was she supposed to abduct him in the name of some ancient law. 

Frisk rolled her eyes, “Stop thinking so much. I captured you and intend to claim you as my prize. It is quite simple.”

“i called you a rude barbarian.”

“Well, I’ve been called worse,” she sassed back, her expression shadowed. And it was then he realized something. How her fierceness guarded from sight something he should have noticed before. A thin, hairline fracture across her soul. Frisk had been hurt. The kind of hurt that made one either hide or lash out. Who could have possibly betrayed her trust enough to scar her in such a way? “Now that we’ve established that I’m not letting you go…” She flicked her wrist, little vine shot up from the ground, twisted together into a neat little braid that curled around her hand. Frisk pulled them up by the roots before walking over to his side, grabbing his wrist and carefully looping the knotted plant around it, then around her own. 

“I, Frisk, Goddess of Spring, claim Sans, God of Death, as my husband. From now until the End of Days, I swear to him my fidelity and love and all that, forever and ever, yadda yadda, and together we are bound by this vow.” That was the shortest and most impatient attempt at a handfasting ceremony that Sans had the misfortune of witnessing. “There. All done. Want another kiss to make it official?”

“...no, not really.”

Frisk shrugged, “Suit yourself.” She tugged her wrist from his, his aura having nearly rotted it off already. “But now you are my husband. Oh, wait, one more thing.” She took off her flower crown and laid it on his head. This creation strangely didn’t wither away, too suffused with her magic. “As heir to the Kingdom of the Heavens, I declare you my prince consort.”

“i don’t think that is how any of that should go.”

“Well it doesn’t matter now, we’re married and that is final,” Frisk crossed her arms. She shifted a moment, before pressing a quick kiss to his cheekbone. “There. It is definitely final.”

“was that supposed to be the consummation of our vows, because i hate to be the bearer of bad news, but a kiss doesn’t ‘seal the deal’ as you seem to think.” 

Any thought that the implication of his words would scare her off faded when she gave him a knowing smile, “You are right. How do you feel about kids? Since it appears our first conversation as wedded couple is about consummation.”

Sans couldn’t hide his flush this time, “...you want kids?”

She shrugged and gave a little sigh, “Part of my domain is fertility. Kids are inevitable.”

As Sans desperately tried to process all that just happened, there was the crunch of natural debris beneath heavy steps and Frisk whirled, stepping close to him, her shoulder pressed to his. From the trees emerged a familiar figure in royal purple, a crown upon her head, fur white and glowing in the dappled forest light. The Queen of the Skies herself. Mother Nature. 

“There you are, my child, I have been looking for you for days. You must desist with this misbehavior and come home this instant. I will not have you causing grief for every god you encounter.” She spotted Sans and groaned, “I see I am too late to stop you from harassing Lord Death. I assume you are not a wayward suitor of hers?”

Sans shook his head, “i was uh, working and i got too close to her...hiding place?”

“No, Mother, I am not going back Above.”

“Frisk, you will do as I say—”

“I already did!”

“Pardon?”

Frisk wrapped her arms around Sans and cuddled against him, “You said I had to get married. That as heir to the throne it was my duty to find a husband.” Her voice dropped to a mutter, “As if by becoming a wife, I’d learn to behave the way you want.” She flashed a too bright grin and pressed her cheek to his, “And did just what you said. I found a husband. In accordance to our laws most ancient, I have claimed Death the Elder as mine until the End of Days. And since I am married, you don’t have control over me as my mother any more.”

Toriel bared her teeth, and Sans felt the air chill, the greenery around them browning with no contribution from himself whatsoever. Nature’s ire was legendary. And that ire was on him. “How dare you,” she snarled. “This must be some trick of yours. I cannot believe you would betray me like this by seducing my daughter!”

“this was not my doing, i did no seducing, there was no seducing on my part!”

“Oh, so you fell for her womanly charms?” Toriel snorted. “Enough of this, as Goddess of Matrimony, I declare your marriage invalid. You will return Above now, Frisk.”

“Y-you can’t do that! Our marriage is c-consummated!” Quiet fell upon them. Frisk clung to him, the vines loosening their hold. “And you should have been more specific if you didn’t want me to marry him. You said I had to find a husband, get married, so I did. I chose S-sans.”

Toriel shook her head, “It doesn’t matter. It is within my right to annul your marriage.”

Frisk’s soul was frantic, beating faster and faster, desperate. She wanted this marriage to be valid. She was silently screaming at the universe for an answer. And he heard. And he had one. He disliked lying, he generally avoided it on principle, but...as he slipped free of the vines, he gathered her against his chest and said, “sorry, my queen, but while you can dispute spoken vows, you cannot dissolve her tie to the underworld. she has eaten fruit from my realm and as you know, ambrosia from the underworld binds those who consume it to it.” Frisk curled her fingers in his robes in relief. He toyed with the ends of her hair, feigning nonchalance, “so we will be going now. heirs to make and all that.”

Before either of them could see Toriel’s reaction, Sans dragged them both through a shadow and into the Underworld. Maybe they could make this whole marriage thing work out?


	2. Progress

**Summary for the Chapter:**

> Written for the Quarantine Frans Week Day 7 Prompt: Progress

**Notes for the Chapter:**

> I was not expecting the reaction everyone had to this silly little role reversal fic. Thank you for your kindness and support

When they emerged from the Void, Frisk stumbled against him, disoriented by her first pass through that land of oblivion that connected all realms. She clung to his chiton, head buried against his chest, a groan of discomfort muffled by Sans’ chest. He stood awkwardly, hands falling away from her, but hovering close, phalanges twitching with the urge to soothe but stilled by his floundering self-restraint. His wife. She was his wife. Maybe. It was all very confusing given the circumstances. Now if only he knew exactly why Frisk married HIM of all the gods. Sans understood why she was in a rush to wed, but why him? Why the Elder Death? He wasn’t Lord of the Underworld any longer. He held little influence politically in the Pantheon unless his brother sought his guidance on an issue. And most of all, they were strangers until he stumbled upon her hiding place.

However, Frisk’s motivations were her own. If she wished to tell him, then she would. Until then, Sans wouldn’t push the issue. Much. 

“Stars above, what in Tartarus did you do?” Frisk peeled herself off him, still pale and admittedly green, like a sailor on his first stint at sea. She blinked, realization dawning on her face with every passing heartbeat. Frisk pulled away and looked around in child-like fascination. Her eyes roamed the natural stone walls and the glittering ceiling, crystals the only source of illumination in an otherwise dark realm. “We’re in the Underworld, aren’t we?” 

Sans nodded, “though it doesn’t look it, we’re within the inner sanctum. the throne room is nearby. i normally would shadow jump directly into my quarters but, uh, it didn’t seem...appropriate.” He felt heat rise to his face as Frisk cast a look over her shoulder, her expression that indescribable one she made before declaring that he would be her ‘bride’. Then, she seemed to make up her mind. Her mouth slanted into an easy smile, her eyes narrowing with feline interest. Sans swallowed as she approached him, a little too much sway in her step to be unintentional. 

“Silly man, I’m your wife. Why would it be inappropriate for you to take me to your room? In fact—” Before she could continue that line of thought, Sans turned sharply away, shoulders pinched. 

“—you must be tired after today’s events, i will show you your room. i mean, if you want it to be your room, it’s a room meant for my wife and you’re my wife or my guest and...let’s just go.” He walked away, all too aware of Frisk’s presence behind him. Their walk felt like it took forever. Sans sensed his brother in the throne room, no doubt holding court, and knew that he would need to talk to him before the day was done. It was probably itching at the younger god that Sans had not only come home early, but brought company. Outsiders were rare to come Below voluntarily. 

Frisk thankfully was too engrossed with their surroundings to ask any questions, though she walked rather close to him, hand brushing his cloak now and then. Soon they reached the royal suites where the brothers Death spent their rare free time. Papyrus wasn’t partial to sleeping, declaring it too much of a bother, but he did like to eat and would loiter in the kitchens. But Sans? He liked his naps. Unnecessary luxury that they were. Which was how he maintained the king’s chambers from his youth despite having stepped down. 

Next door was the queen’s chambers, kept maintained but mostly empty given neither brother had been actively looking to wed. Sans opened the door and stepped inside, motioning to the feminine furniture that his younger self gathered when he’d been a more optimistic god. He explained how these rooms were hers to with what she wished, guests and servants both would only be allowed within given her permission. He opened the door to the bedroom. It was outdated but no less grand, the bedding all woven of spider silk, the floor and walls covered with colorful rugs and tapestries. “through that door is a bath chamber. There are hot springs nearby as well that can be reached through a hall connected to that room.” 

He shifted a little, “there aren’t any clothes here, but if you wish, i can request for some to be tailored posthaste, or take you above to visit a human market. cost is not an issue.” Frisk padded around the room, peeking through into the bath and curling her toes into the rugs. It was then she turned her attention to the far wall opposite of the bathing room and the askew tapestry there. Noticing her stare, Sans swallowed and pulled it back, revealing a door, “this r-room was meant for my wife as i said before, and was to be hers to decorate and do with what she wished. and this door connects this room to...mine. l-leave that door adjar if my c-company here is w-welcome.” He cleared his throat and once more attempted a firm tone, wagging a phalange, “don’t come into my room if my door is shut, and i won’t come in here without your permission either.”

Frisk crossed her arms, “What if I don’t want us to have separate rooms?”

“w-what?”

“You said it yourself...heirs to make and all that,” she stalked towards him, arms looping around his neck, a teasing smirk on her lips. “Hard to do with a door between us.”

Sans shivered, momentarily stupefied, lost in that tempestuous stare. But he soon regained himself, her soul singing truer words than she spoke aloud. She was still frightened. Still nervous. Still desperate. Her clinging to him like this was the audacity of a determined soul attempting to change its course by any means necessary. Even seduction. It pained him to admit it, but as lovely as his unexpected wife was, and how soft her kisses, he couldn’t bring himself to ignore that scar on her inner being or pretend that she wasn’t manhandling him because she thought she had to in order to stay ‘safe’.

He reluctantly peeled her arms off of him, “you must be hungry. I will bring you something to eat...then i must take care of some business. the king needs to be informed that we have a guest.”

“Guest?” Frisk propped her hands on her hips, eyes narrowed with overt annoyance. “A wife isn’t a guest, bonehead. Also, you mentioned something about fruit to my mother. Bring me some of that, maybe you’ll stop thinking of me as some guest if I’m bound to the Underworld or whatever.” She puffed her cheeks, “Well, go on.”

“you want to eat...lady spring i must advise precaution—”

“I said I wanted the stupid fruit!” She stomped her food, that spoiled, childish reputation rearing up and lashing out. “We are married. And I want to stay here.” His breath hitched as flowers began to bud around her. Not cute little flowers that one might see and pluck to tuck in one’s hair, but the wild, prickly kind with sticky leaves and stems lined with thorns. Vines began to crawl up the walls, as ominous as serpents and even more likely to strike. “I won’t go back, understand? You’re stuck with me, forever and ever, no matter what Mother says, even if that means I go looking for this fruit myself!”

Sweat beaded on Sans’ skull and he did the one thing he could think to do, he scooted closer, the hem of his robes tangling in the plants, wilting them, and touched her face. She stopped ranting to stare at him. Her skin was soft. Her eyes damp with unshed tears. “very well, my lady. i will bring you your requested ambrosia. just be aware that if you choose this path, to eat the fruit, that regardless of what happens between us, you will be forever tied to the underworld. you will be, in essence, one its goddesses for the rest of your immortal existence. should you return above to the surface you will inevitably be drawn back here, and you will never be fully content when living above. eating ambrosia from the land of the dead is a vow in itself.”

Frisk met his gaze with vivid determination, “Good.”

Sans bowed his head and stepped away, “make yourself comfortable, lady spring.”

“Frisk. I told you before, call me Frisk.”

“yes, pardon...frisk. i will be back.”

Sans stepped into a shadow and slipped through the Void, reappearing behind one of the columns in the throne room. Papyrus continued to hold court, examining each soul that came into his care. While Sans was the one gifted with Judgement, able to discern the true nature of every soul, his brother handled the management. He sorted every one that came, weighing Sans’ judgement into his final decision. It was a heavy burden, but somehow, it had yet to callous his gentle, merciful soul. Kingship numbed Sans when the Underworld was his alone. Left him cold.

Eventually, Papyrus called a halt to his endless duty, the dead would stay dead, there was no hurry, not really. And when the room was cleared, he rose from his throne, golden crown glittering on his brow, robes sweeping the ground. He offered Sans a tired smile, “BROTHER, YOU ARE HOME EARLY...AND WITH A GUEST, I DO BELIEVE.” 

“yeah, uh, she’s a permanent guest.”

Papyrus blinked and all weariness fled, “SHE? OH, DON’T TELL ME THAT YOU HAVE BROUGHT HOME A LADY FRIEND AT LAST?”

Sans shrugged, “not really a lady friend as much as...a wife.”

There was a pause as the information made the wheels in Papyrus’ skull turn and rattle before clicking into place, “WIFE? YOU DID NOT TELL ME YOU WERE SEEING ANYONE..”

“it was a bit of a rushed deal. real impromptu.”

“LOVE AT FIRST SIGHT?”

His soul pumped a little faster despite his wishes, “...sure.” Sans allowed himself to smile, “you could say it was fate.”

Papyrus drew in a sharp breath, “SO SHE IS THE ONE?”

“yeah.”

The younger god of Death cheered and swept Sans up into his arms, swinging him around, “I MUST MEET HER! OH, BUT NOT NOW. I HAVE TO RETURN TO WORK...AND SO DO YOU FOR THAT MATTER...HM.”

“i think she needs some time to settle anyway, papyrus. i’m going to get her some food and make sure she’s settled before i head out again. though i am bone-tired. heh.”

Papyrus huffed and dropped Sans, “BEGONE WITH YOU. I KNOW WHEN YOU’RE ABOUT TO START MAKING A NUISANCE OF YOURSELF.”

“awe, but papy~”

“SHOO!”

Sans chuckled, watching as Papyrus returned to the throne, a little more hopeful. He slipped back through the shadows, emerging in one of the oases that dotted the Underworld. They were little reminders that the realm of the dead wasn’t a dead place and were some of the few areas where Sans could interact with plants without killing them instantly. And within these special places where life mingled with death grew fruit trees. Ambrosia. Food of the gods. There were many kinds of ambrosia, every realm had a food that could snuff out the soul of a mortal if consumed, but the Underworld’s was unique. It tied those that ate it to the Underworld, to death, meaning in a strange way, it ‘killed’ every being that consumed it, even if it did not shatter their soul. 

He wandered deeper into his chosen orchard, ignoring the stares and whispers of the nymphs that lived here, elusive as wraiths and just as eerie, changed forever by the eons of living Below, not quite dead and not quite alive. Sans plucked a pomegranate from a tree and tucked it away in his robes. Just one seed was enough. Sweat beaded on his skull as he whisked his way to the kitchens, swiping a selection of simple foods for his new bride. Bread and cheeses mostly. A few thin slices of cooked lamb. He pilfered a knife long enough to carve open the fruit, red juices staining the blade and his phalanges as he arranged everything in a bowl. Then he was off again, emerging outside of Frisk’s antechamber. He knocked. 

It wasn’t long before Frisk cracked open the door, then threw it open, snatching the bowl from him quite as a viper. She proceeded to dig her fingers into the pomegranate to free the seeds and devour them in a way that could only be described as spiteful. Each and every one. After, she grinned at him before shoving a piece of bread in her mouth. When was the last time she ate? Gods didn’t have to eat, but it was pleasant and nourishing, same as sleep. Apparently he was watching agog because Frisk scarfed down the bread and wiped the crumbs from her chin, “What? I said I would eat the fruit and I did.”

“i...wasn’t expecting your enthusiasm.” He received a flat look. “well, enjoy your meal. If you would like i can take you back above to shop for clothes or…?”

“M’staying here. I don’t need extra clothes.”

Sans eyes the ragged edge of her chiton, “will you at least allow someone to measure you? as i said before, i can request some clothes to be tailored.” 

“...Later. Not now.”

“very well. I have to return to work. if you need anything at all, pull on the cord by your bed, a servant will come to aid you.” Sans straightened his robes. “take care, frisk.” Before he could leave, she grabbed his sleeve with a free hand, stilling him.

“No kiss goodbye?”

Sans swallowed, plucked her hand from his sleeve, and pressed her knuckles to his teeth. Then he stepped backwards through the Void.

.

Frisk stared at the spot where her husband disappeared and huffed, “That wasn’t what I meant, bonehead.” She remained standing there for a long moment before turning and flopping down onto a chair, the bowl of food in her hands less appealing. However, it had been a long time since she ate anything beyond what she scavenged in the wilds, mushrooms and edible plants, not wanting to exercise her powers too much and risk her mother finding her. So she kept putting morsels to her lips. 

Marrying Sans was the best decision she ever made, right alongside running away from her mother’s home where she was kept ‘safe’. Secluded. A shameful secret. If she was never going to do right by her mother’s name, then by the gods, she would do right by her own. And if that meant choosing a husband that her mother would never approve, then all the better. It wasn’t that Toriel hated the brothers Death (well, before this whole affair). But they were strange and dangerous and not gods for a nature goddess like herself to associate with unless absolutely necessary. There was a reason they were feared. 

She had not planned to marry today, or soon even, fine with evading Mother Nature for the time being. But when she saw Sans, saw the distracted way he examined a stupid rock of all things, Frisk realized that it may very well be her one and only chance to put her wild, haphazard plan into action. She didn’t expect to catch him by surprise...or for him to sass her. She wondered then if what she was doing was crazy, but, somewhere in the depths of her soul, she knew. This was it. He would be the one she would marry. Of course the whole process went utterly poorly and then her mother arrived and started declaring her marriage invalid. She was prepared for Sans to leave her to her Mother’s mercy (she did attack and marry him against his will), but he surprised her. He seemed to not only accept but want their marriage. 

Frisk laid the bowl to the side and wandered to her bedroom.

Mother couldn’t reach her here, she assured herself. It was one of the reasons she chose Death. And now she ate the fruit to bind her soul to the Underworld, so she had to be safe. Sans couldn’t be rid of her. She crossed her arms and held herself, head bowed. He was hers now. All hers. And she planned on keeping him, even if that meant…

She drew in a breath, face heating. Flirting was a fun and nuanced game, but as a wife, there were expectations on her. Expectations Sans didn’t seem to have. Yet. It would be easier to get the awkward bits out of the way early, to seduce him and further solidify their bond, than to dance around the ifs and maybes. Except she’d never seduced anyone and wasn’t quite sure how to go about it. Sans did at least turn delightful shades of blue any time she flirted with him, which was promising. Maybe if she could catch him with vines again so he didn’t sneak off before she was done saying her piece. 

With a sigh, she fell face first onto the bed, resigned to dwell in her thoughts until Sans returned. She wasn’t exactly in a mood to explore. Or talk to anyone. Or do much of anything. Frisk curled up and closed her eyes, attempting to get comfortable. But as time ticked past, she found it impossible to sleep. She flipped and rolled and eventually got up, frustrated, and decided to try a bath. Warm water helped soothe away some of her aches but when she returned to bed and once more attempted sleep, she again found it elusive. 

Having long since lost track of the time, though she was certain it was late at night given her heavy eyelids, Frisk stared at the ceiling, absently connecting the crystals with her eyes. Eventually, her eyes slid down the wall to the tapestries and to one in particular. She puffed her cheeks, annoyance flaring at Sans’ insistence at separate rooms, but after a heartbeat, she found herself on her feet and at the door, opening it. The hallway wasn’t dark like she expected, but illuminated by more of the crystals, the walls like the heavens above during a clear night. Frisk padded through the hall, hand skimming the stone and paused when she reached the other side. The door was shut.

“...Sans said to not enter his room if the door was shut and he would extend the privilege…does that mean if I go in that he’ll come into my room any time he pleases?” Frisk murmured, considering how she felt about the matter. It took all of a minute before she was opening the door and creeping inside. It was dark. Very dark. Far darker than her room. But the glow of the hall cast enough light for her to see his bed. Inspired, Frisk strolled up to it and sat on the edge, finding it just as luxurious as her own. But the room felt different. She could almost sense him here, cool as a river stone yet very much alive. 

She crawled into the center of the bed and yawned. Frisk made up her mind. She lived here now. This was her bed. Hers and her husband’s. If he didn’t like it he could tell her himself when he came back. With a stretch, she curled up, sleep coming swifter than expected. 

.

Later, before the first rays of dawn, Sans returned from his duties Above, hoping for a quick nap. But when he arrived, he saw a lump in the middle of his bed. A lump in the shape of his very lovely little wife. Sans spun on his heel and fled through the shadows, reappearing in Papyrus’ chambers. The younger god didn’t like sleeping and was enjoying an early morning snack when Sans popped in beside him.

“papyrus! help. i don’t know what to do.”

.

Frisk woke in the morning, none the wiser to her husband’s return and subsequent flight.


	3. Flirt

**Notes for the Chapter:**

> Written for Fransweek 2021 | Day One: Flirt

Sans was avoiding her.

Either that or he was an insufferable workaholic.

Possibly both.

Regardless, Frisk had every intention of catching her wayward spouse at the first opportunity before explaining to him that it wasn’t very nice to leave your new wife all alone for days on end. She was BORED! Of course, she could leave their chambers and explore, but there was an unease that struck her each time she reached for the door leading into the fathomless tunnels of the Below. What if eating the ambrosia wasn’t enough for the Underworld to accept her as belonging? What if its denizens sought to extinguish her lifeforce? What if Death’s younger brother, the crowned King of the Dead, decided he didn’t like her and crushed her soul in his hands! Frisk banished that last thought with a scoff. The younger brother wasn’t known for his ruthlessness. 

Unable to tolerate cowering in her chambers any longer, Frisk eventually gave into her basic urges. Steeled against the possibility of being hurt, she thrust up her chin, eyes flashing with determination, and threw open the door, stalking out like she owned the Underworld. In her wake, her domain defied death itself, and a path of wildflowers bloomed. Onwards she moved until she entered a vast cavern full of whispers and mist, where upon a simple throne of gold sat a tall, hooded figure that was most certainly not her husband. Frisk was tempted to walk into the midst of the room and investigate, but she remained leery of Death the Younger. If rumors held true, he was a stickler for the rules and on friendly terms with that self-absorbed metalbrain, Mettaton. How anyone could like that vain, egotistical mockery of divinity, she’d never know. 

(The fact that mother considered him a proper suitor until she hurt his shiny pride was hardly an important matter. Not her fault he couldn’t handle a dip in the mud from which he came!)

Frisk diverted her journey from the throne room and walked and walked and walked. She walked until the tunnels became vast caverns, the air humid and thick with the promise of water. And she kept walking until her toes were buried into the banks of one of the Underworld’s many rivers. All along it grew odd fungi that glowed the same cyan as the water itself, providing a soft but familiar light akin to the many crystals that grew in tall columns down here. To call the Underworld a dark place was a misnomer. It wasn’t as bright as the Surface during the daylight hours, nor did it shine with a gilded glory like the heavens Above, but it shone in its own way. 

Hands behind her back, Frisk padded along the river, hardly a thought in her head, until she saw it. A sunbeam cutting through from Above, beneath it, a patch of green. A smile split Frisk’s face and she darted to it, giggling like a child she stepped foot upon the little spot of paradise. Oh she was liking her decision to stay down here all the more! Why would she ever want to go back when the Underworld had LIFE! A nature goddess at her core, Frisk giddily skipped and spun about, her ragged chiton swirling around her legs as she relished in her discovery. There were trees and bushes and so many fruits and flowers. Oh! It had to be in an oasis like this that the ambrosia grew. 

Content to indulge in her domain, Frisk gave the passage of time no heed. She had been alone for so long, always running from suitors and her mother, that it was a familiar state. What was a few days coaxing plants into their fullest glory in the grand scheme of eternity?

“Bring her back, Sans.”

To say Sans was feeling haggard and a little harassed was an understatement. He just wanted to do his job, and Lady Nature was adamant on interrupting his sacred duty. No wonder Frisk had been practiced in stealth and deception—Toriel was a master at finding gods upon the Surface, for the mortal world was her domain. He wondered, idly, if she knew exactly where her husband hid and just let him alone after he abandoned his throne upon Asriel’s death. Toriel’s wrath towards him after he declared war on the mortals was renowned, and she did all but usurp him to protect them. 

And then, after the throne of the heavens was broken in two, she was alone to hold it all together. Sans watched her fill the void with adopted mortals. Little demigods like Chara. And one-by-one he took them from her like Chara. She didn’t hold their deaths against him. They were hero souls, wards of hers though they might be, and destined to eventually die. But the last one was different. The last mortal child wasn’t like the others. 

The last of the demigods was of Toriel’s own ichor.

She hid her zealously away. Sans barely thought of the girl...until it was known that she was a demigod no longer, but a goddess of her own right. Toriel played a dangerous gamble with Frisk’s life, for mortals, even demigods, didn’t just become gods. They had to consume ambrosia and live...and some ambrosias needed special preparation or they were toxic to even the divine, a fact that the young prince and his mortal friend discovered too late. Unlike pomegranates harvested from the Underworld’s orchards, the goldenflowers of the heavens could only be consumed as a tea. 

“Sans, I know you can hear me. Sans...LORD DEATH! YOU WILL LISTEN TO ME!”

He couldn’t ignore the queen any longer, no matter how much he simply wanted to finish the reaping that needed done and return Below for a short nap. So he pulled down his hood and faced her, “i am busy, lady nature.”

Toriel’s aura was that of a walking thunderstorm, “Return her. Humoring her fit of rebellion doesn’t suit you.”

“i do not understand what you mean. lady spring is my wife. what rebellion am i humoring by her living with me in the underworld?”

“This joke...this….FARCE has gone on long enough. Cease making a mockery of marriage and return her to me. She is the heir to a Delta throne. A good match is crucial should there ever come a day that she needs to assume the title of Queen.”

Sans cocked a brow and laid a hand upon his chest in feigned hurt, “i was once a delta king before my abdication. one would think you would approve the match.”

Toriel’s expression softened, “Your loyalties are to the Underworld. You can never be the King of the Skies.”

“no. i cannot. i surrendered that possibility quite happily a long time ago. the underworld would take offense, i believe, if my loyalties altered.” 

“Then you must understand. Please. Convince her to come home.”

He sighed and shook his head, “as i told you before, my lady, that is impossible. her home is below. she is bound same as i. she has eaten ambrosia from my realm.”

“Liar!”

Electric with grief, her aura crackled, and the earth began to tremble. Sans frowned and stood his ground. His own aura darkened and roiled, “do not challenge me so carelessly, lady nature.” The greenery around them greyed and rotted in a violent instant, “i will not endure insults towards myself or my marriage. so mind your tongue before i carve it out.”

Toriel recoiled like she was slapped, the storm in her eyes clearing, and she staggered back a single step. Tears gathered in her eyes, “I...I just want my daughter back. I want her safe and happy. Please. I have lost so many children, I cannot lose her too.”

“children grow up, lady nature,” Sans murmured. “she is married, not dead. i believe we’re done here.” Knowing he would get no more work done until Toriel returned Above, Sans stepped backward through a shadow and plunged into the realm Below.

She wasn’t in her room. Or his. 

Sans at first thought she was asleep again (as she had made a habit of curling up in the middle of his bed for some bizarre reason) but when he dared investigate his chambers, she was nowhere to be found. When he brought the issue to his brother that first night, Papyrus had laughed at him, told him to go take a nap with his new little wife...then winked. Despite what he had told Toriel when he first brought Frisk Below, consummation and the making of little godlings wasn’t exactly on his mind. She was a stranger to him. And strangers didn’t go crawling into beds while the other was sleeping! That was rude.

(Even if it was his bed she insisted on sleeping in…)

That said, her absence was like brushing against Toriel’s aura once more, and jolted him from his haze. The Underworld was a dangerous place. What if she was hurt! Though he was no longer its king, the Underworld did not abandon its oldest companion when he bid it for aid and answers. Offering little flashes and images in its own manner of awareness, Sans followed its lead and leapt through the shadows until he spotted the place that it showed him—a now overgrown oasis surrounded by a wall of vines and thorns. It utterly brimmed with Frisk’s power. The tiniest shiver passed through him as he recalled how she was able to defy his own domain, something that even Lady Nature could not do. 

Assured of her safety, Sans could have walked away, but curiosity won out. He wandered closer and attempted to find a path through the barrier. A poke here. A prod there. He could wither the vines a degree, but without force, he couldn’t break them. Satisfied, he made to walk away...but in a flash of déjà vu, vines erupted from the ground and ensnared him. He knocked on Spring’s door...and she answered.

“Why look who it is,” Frisk purred as she parted the barrier and saunted up to him. “My dear husband who has left me all by my lonesome for all this time. And right after we were married!” Her pout was short lived as she wrapped her arms around him. Sans felt his skull heat. Oh...right. Despite not needing to persuade him to help her anymore, she continued to flirt with him. The vines tightened. “Now that you’re here...I don’t plan to let you go until you make up for abandoning me on our wedding night.”

“i didn’t abandon you. i was working!”

Frisk winked and ran a finger down his cheekbone, “I guess I can forgive you for a kiss~”

Sans wriggled, “l-look, i get that you may have certain ideas about marriage.” Her mother was the goddess of matrimony. “b-but i don’t expect...i...you don’t…” He caught his breath and his words. “you don’t have to pretend you desire me. i can see your soul, my lady, and...neither of us are ready for...for more.”

Her hand paused in its flirtatious path and he peeked at said soul that he could always see. He watched it flare bright with determination, saw the way it strained against its scar. She was a strong and beautiful woman who had been hurt very badly. He could sense her desperation, her fear and anxiety with every touch and coaxing word. As nice as it felt for her to lavish adoration upon him and to imagine that his wife wanted him, it was just an act. He wouldn’t take advantage of her vulnerability. 

Suddenly, the vines tightened to the edge of pain, and he wished he could say it dampened his dawning interest in the wild little barbarian that was his fated bride. But her power was magnificent...alluring in its danger. 

“Don’t tell me what I want or how I feel,” Frisk warned. 

“apologies.”

The vines’ grip relaxed and she crossed her arms, “Do you find me so repugnant that you can no longer bring yourself to remain in my presence? Does the thought of kissing me repulse you?” Fear and anger guarded her soul like a field of brambles. He needed to tread carefully lest he bloody himself on the thorns. “Just tell me and I will stay out here. I won’t bother you anymore. You can’t make me go back Above. It’s too late for that. I ate the ambrosia!”

“now when did i ever say any of that, lady spring?” Sans murmured. “you are a very beautiful woman and intimacy with you would be easy, but...it would not rest easy on my conscience if i took advantage of you.”

Wildness sparked in her eyes as a smirk crossed her lips and she tossed her untamed hair, “Oh is that it~? What if I took advantage of you?”

Sans choked on a retort. That wasn’t the direction he planned on this conversation going! He could only sputter and blink as she closed in on him and pushed him gently to the ground to lay in a bed of grasses and wildflowers. She toyed with his emblems and rested her weight astride his hips, looking to the world like a mischievous nymph that had caught herself a wayward mortal to play with. 

“Now...about that kiss~?”

**Author's Note:**

> The question asked: How and why would Fated!Frisk be the one to kidnap herself a spouse?
> 
> The result: Bamf!Frisk as an established Goddess. Nervous!Sans who was never the feared ruler of the dead. And a domineering Queen Toriel that has driven her daughter away. 
> 
> There may be more of this in the future. It was too much fun.
> 
> [Want more? Check out the Fated blog Shayromi and I run for this AU.](https://fated-au.tumblr.com/)

**Works inspired by this one:**

  * [Undertale prompt 2020: Day 28: Family](https://archiveofourown.org/works/26699794) by [Zeliez](https://archiveofourown.org/users/Zeliez/pseuds/Zeliez)




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